PROJECT SUMMARY/ABSTRACT The overall objective of this proposed research is to develop laser-based methods for the selective removal of dental caries and composite restorative materials using an integrated approach of computer-controlled laser- scanning coupled with methods of feedback. In addition to eliminating unpleasant noise and vibration associated with conventional dental handpieces, lasers deliver unparalleled precision, sterilize/remove tissue, and offer practical advantages such as decreased surgical time and smaller handpieces. Under appropriate laser conditions, lasers can confer a protective barrier on the enamel against future caries risks and enhanced adhesive properties for restorative materials. The objective of this proposal will be achieved through the following two specific aims: (1) Test the hypothesis that near-IR imaging systems can be combined with IR laser systems for the image-guided selective ablation of carious lesions; and (2) Test the hypothesis that spectral analysis can be used with a pulsed CO2 laser system for the selective removal of dental composites and sealants. These fundamental studies will significantly further our knowledge of the interaction of laser radiation with dental hard tissues and aid the development of safer and more effective feedback-guided laser systems over existing methods for the removal of dental caries and restorative materials. Furthermore, laser feedback systems have the potential to globally advance the standard of healthcare with increased conservative care for cavity preparations and dental restoration replacement procedures.